Archamoebae

{{Short description|Phylum of protists}} {{Automatic taxobox | fossil_range = | image = Entamoeba histolytica.jpg | image_caption = ''Entamoeba histolytica'' trophozoite | display_parents = 4 | taxon = Archamoebea | parent_authority = Cavalier-Smith 1998 | authority = Cavalier-Smith 1993, sensu Cavalier-Smith 2004 | subdivision_ranks = Orders and families | subdivision= * Tricholimacidae * Endamoebidae * Entamoebida ** Entamoebidae * Pelobiontida ** Pelomyxidae ** Rhizomastigidae | synonyms_ref = | synonyms = * Karyoblastea Margulis & Schwartz 1982 * Peloflagellatea Goodkov & Seravin 1991 * Caryoblastea * Entamoebea Cavalier-Smith 1991 * Rhizoflagellata Saville Kent 1880 * Mastigamoebomonada Starobogatov & Seravin 1980 }}

The '''Archamoebae''' are a group of protists originally thought to have evolved before the acquisition of mitochondria by eukaryotes.<ref name=Evolution>{{cite book|title=The Evolution of Parasitism - A Phylogenetic Perspective |isbn=9780080493749 |editor=Littlewood T |vauthors=Williams BP, Keeling PJ |url=https://books.google.com/books?id=_fAQGEJobT0C&q=Archamoebae&pg=PA30 |access-date=20 February 2018 |pages=30–31|date=2003-12-09 }}</ref> They include genera that are internal parasites or commensals of animals (''Entamoeba'' and ''Endolimax''). A few species are human pathogens, causing diseases such as amoebic dysentery. The other genera of archamoebae live in freshwater habitats and are unusual among amoebae in possessing flagella. Most have a single nucleus and flagellum, but the giant amoeba ''Pelomyxa'' has many of each.

==Description== Archamoebae are a diverse group of amoebae. Many have flagella for motility, while others do not. They grow in the absence of oxygen, though some can tolerate small amounts. Most described species of Archamoebae either lack mitochondria or are described to have reduced mitosomes.<ref name="EvoArchamoebae">{{cite journal|doi=10.1016/j.protis.2012.11.005|pmid=23312407|title=Evolution of Archamoebae: Morphological and Molecular Evidence for Pelobionts Including Rhizomastix, Entamoeba, Iodamoeba, and Endolimax|journal=Protist|volume=164|issue=3|pages=380–410|year=2013|last1=Ptáčková|first1=Eliška|last2=Kostygov|first2=Alexei Yu|last3=Chistyakova|first3=Lyudmila V|last4=Falteisek|first4=Lukáš|last5=Frolov|first5=Alexander O|last6=Patterson|first6=David J|last7=Walker|first7=Giselle|last8=Cepicka|first8=Ivan}}</ref>

==Habitat== They thrive and live in soil, freshwater, and marine habitats. ==History== The group Archamoebae was proposed by Thomas Cavalier-Smith in 1998 as part of the Archezoa, a newly-proposed group to include eukaryotes that had diverged before acquisition of mitochondria and other common eukaryotic cell features.<ref name="pmid9809012">{{cite journal |author=Cavalier-Smith T |title=A revised six-kingdom system of life |journal=Biol Rev Camb Philos Soc |volume=73 |issue=3 |pages=203–66 |date=August 1998 |pmid=9809012 |doi= 10.1111/j.1469-185X.1998.tb00030.x|s2cid=6557779 }}</ref><ref name=Keeling>{{cite journal|url=http://www3.botany.ubc.ca/keeling/PDF/98King.pdf |access-date=20 February 2018 |title=A kingdom's progress: Archezoa and the origin of eukaryotes |author=Keeling PJ |journal=BioEssays |volume=20 |pages=87–95 |doi=10.1002/(sici)1521-1878(199801)20:1<87::aid-bies12>3.0.co;2-4|year=1998 }}</ref> Early molecular trees based on rRNA supported this position, placing several Archamoebae genera as separate groups that diverged from other eukaryotes very early on, suggesting that the absence of mitochondria was a primitive condition.<ref name=Keeling/> However, soon thereafter genetic remnants of mitochondria were found in various Archamoebae, suggesting that these organisms had diverged after the evolution of mitochondria, but had lost their mitochondria over time, and are more closely related to various amoebae and slime molds.<ref name=Evolution/> ==Phylogeny== The following cladogram summarizes the known relationships between the different families of Archamoebae.<ref name="EvoArchamoebae"/> {{clade|label1='''Archamoebae'''|1={{clade|label1=Entamoebida|1=Entamoebidae|label2=Pelobiontida|2={{clade|label1=Mastigamoebina|label2=Pelomyxina|1={{clade|1=Mastigamoebidae|2=Rhizomastixidae}}|2=Pelomyxidae}}}}}} ==Taxonomy== Infraphylum '''Archamoebae''' Cavalier-Smith 1993 stat. nov. 1998<ref name="EvoArchamoebae"/><ref name="Cavalier-Smith, Chao & Lewis 2016">{{cite journal | vauthors = Cavalier-Smith T, Chao EE, Lewis R | title = 187-gene phylogeny of protozoan phylum Amoebozoa reveals a new class (Cutosea) of deep-branching, ultrastructurally unique, enveloped marine Lobosa and clarifies amoeba evolution | journal = Molecular Phylogenetics and Evolution | volume = 99 | pages = 275–296 | date = June 2016 | pmid = 27001604 | doi = 10.1016/j.ympev.2016.03.023 | doi-access = free }}</ref><ref>{{cite book | date=2016| last = Silar | first = Philippe | name-list-style = vanc | chapter = Protistes Eucaryotes: Origine, Evolution et Biologie des Microbes Eucaryotes| url=https://hal.archives-ouvertes.fr/hal-01263138|pages=1–462 | title = HAL archives-ouvertes | isbn = 978-2-9555841-0-1 | chapter-url = https://hal.archives-ouvertes.fr/hal-01263138/file/Protistes_Eucaryotes.pdf }}</ref><ref>{{cite journal | vauthors = Kang S, Tice AK, Spiegel FW, Silberman JD, Pánek T, Cepicka I, Kostka M, Kosakyan A, Alcântara DM, Roger AJ, Shadwick LL, Smirnov A, Kudryavtsev A, Lahr DJ, Brown MW | display-authors = 6 | title = Between a Pod and a Hard Test: The Deep Evolution of Amoebae | journal = Molecular Biology and Evolution | volume = 34 | issue = 9 | pages = 2258–2270 | date = September 2017 | pmid = 28505375 | pmc = 5850466 | doi = 10.1093/molbev/msx162 }}</ref><ref>{{cite journal | vauthors = Pánek T, Zadrobílková E, Walker G, Brown MW, Gentekaki E, Hroudová M, Kang S, Roger AJ, Tice AK, Vlček Č, Čepička I | display-authors = 6 | title = First multigene analysis of Archamoebae (Amoebozoa: Conosa) robustly reveals its phylogeny and shows that Entamoebidae represents a deep lineage of the group | journal = Molecular Phylogenetics and Evolution | volume = 98 | pages = 41–51 | date = May 2016 | pmid = 26826602 | doi = 10.1016/j.ympev.2016.01.011 | doi-access =free | hdl = 11104/0281463 | hdl-access = free }}</ref> * Class '''Archamoebea''' Cavalier-Smith 1983 stat. nov. 2004 ** Order Entamoebida Cavalier-Smith 1993 *** Family Entamoebidae Chatton 1925 em. Cavalier-Smith 1993 **** Genus †''Entamoebites'' Poinar & Boucot 2006 **** Genus ''Entamoeba'' Casagrandi & Barbagallo 1895 ** Order Pelobiontida Page 1976 em. Cavalier Smith 1987 *** Suborder Pelomyxina Starobogatov 1980 **** Family Pelomyxidae Shulze 1877 em. Cavalier-Smith 2016 ***** Genus ''Pelomyxa'' Greeff 1874 ***** Genus ''Mastigella'' Frenzel 1892 *** Suborder Mastigamoebina (Frenzel 1897) Pánek et al. 2016 **** Family Rhizomastigidae Cavalier-Smith 2013 ***** Genus ''Rhizomastix'' Aléxéieff 1911 **** Family Mastigamoebidae Goldschmidt 1907 ***** ?Genus ''Craigia'' Calkins 1913 ***** ?Genus ''Dobellina'' Bishop & Tate 1940 ***** ?Genus ''Pansporella'' Chatton 1925 ***** ?Genus ''Martineziella'' Hegner & Hewitt 1941 non Chalumeau 1986 ***** ?Genus ''Dinamoeba'' Leidy 1874 non Pascher 1916 ***** Genus ''Endolimax'' Kuenen & Swellengrebel 1917 ***** Genus ''Iodamoeba'' Dobell 1919 ***** Genus ''Mastigamoeba'' Schulze 1875 '''Archamoebae''' ''incertae sedis'' * Genus ''Endamoeba'' Leidy 1879 * Genus ''Mastigina'' Frenzel 1897 * Family Tricholimacidae Cavalier-Smith 2013 ** Genus ''Tricholimax'' Frenzel 1892

==References== {{Reflist}} {{Eukaryota}} {{Amoebozoa}} {{Amoebozoa diseases}} {{Taxonbar|from=Q589993}}

Category:Conosa Category:Infraphyla Category:Taxa named by Thomas Cavalier-Smith